The surface electronic structure of p-type wurtzite GaN(0001̄) 1×1 grown by molecular beam epitaxy has been investigated using synchrotron radiation excited angle resolved photoemission spectroscopy. Four discrete surface states were clearly identified and characterized. All the states were removed by exposure of the surface to atomic hydrogen. Three of the states were of pz orbital character, while the fourth is derived from s orbitals. Three of the surface states lie below the bulk valence band maximum throughout the surface Brillouin zone, and one surface state was observed to disperse into the bulk optical band gap. Comparison with theory suggests that this surface state is Ga-derived, consistent with a model of Ga-terminated, but N polar, GaN. The other three surface states compare well with states observed earlier from n-type GaN.
|Number of pages||7|
|Publication status||Published - 10 Nov 2000|